Nov 12, 2018

Weed management for organic farms focus of USDA award

Weed management strategies for organic vegetable growers, including challenges to implementing them, will be the focus of a more than $1.9 million grant from the United States Department of Agriculture National Institute of Food and Agriculture to the University of Maine.

The research will be led by Eric Gallandt, a UMaine professor of weed ecology and management, and Dan Brainard, a Michigan State University associate professor of sustainable vegetable production. They will investigate different methods of weed management for organic growers and the reasons some vegetable farmers do not implement them. The goal is to address these barriers, and integrate cultural and mechanical strategies for improved weed management on organic farms.

One of the most prominent challenges organic farmers face is weeds, which they often manage with cultivation, crop rotation and cover cropping. However, many organic farmers rely on outdated equipment and less effective weed management tools that, when combined with natural dispersal of weed seeds, allow for stable or increasing weed populations.

Gallandt proposes a cultural weed management approach focused on practices for depleting the weed seedbank, the reserve of viable weed seeds present in soil, along with advanced, effective cultivation tools to reduce weed populations over time.

Most organic vegetable farmers focus on the “critical weed-free period,” cultivating for an early crop size advantage to minimize yield loss, according to the researchers, who note the problem of weeds is sometimes neglected in the process.

However, management focused on seeds and seedlings will create a positive feedback loop to reduce the weed seedbank.

Both weed seedbank management strategies and cultivation tools, including between-row tools, in-row tools and stacking tools, can improve mean efficacy of weed management practices and reduce variability of the outcomes, but few farmers have adopted these strategies.

Lack of access to some tools, beliefs that the practices are not compatible with a particular farm, and lack of evidence-based research on the subject discourage farmers from implementing these weed management practices.

“Our aim is to work with innovative farmers, equipment manufacturers and researchers to address these barriers to adoption,” said Gallandt.

The research team’s goals are to develop and demonstrate advanced weed management practices that will result in decreasing weed populations and increasing profitability, and engage stakeholders through on-farm research, data-driven decision making, and exchange of knowledge and experiences between farmers.